Expansion Tanks

What is an expansion tank, and why do you need one?

Expansion tanks are installed in closed water systems to handle the expansion of water as it is heated.  Typically, closed systems would have a pressure reducing valve.  In some hot water re-circulation systems the check valves installed created a closed system, necessitating the need for an expansion tank.  Typically an indicator of excessive pressure would be the relief valve on a hot water heater periodically leaking.